<span>Archaeas and Bacterias are both Prokaryotes. Both used to be classified in Monera kingdom, but later genetists found that they have actually very different genes, despite they both have a similar metabolism. So they think they have a totally different evolutionary origin and they decided to classify them in 2 different domains. The other domain, Eukarya, includes every other organism (all the ones who are not Prokaryots), which are: plants, animals, fungi and protists.</span>
Point mutations are the substitution of a single nucleotide, which creates a different codon and therefore a different amino acid. the incorporation of a different amino acid in the protein can completely disrupt the normal function of proteins.
Antigen: is a a foreign substance or toxin that causes a immune response.
Antibody: it is a blood protein that is produced in response to an antigen.
White blood cell: also called a leukocyte and is a cell that counteracts against antigens.
Specific: If your're talking about the biology definition then it is, of or pertaining to a species.
Pathogen: a virus or bacteria that can cause a disease.